o-200 stick valve ?

do they have to remove the carb to adjust the float level or adjust the way it is jetted ?
 
bobkiksass said:
do they have to remove the carb to adjust the float level or adjust the way it is jetted ?
Click to expand...

To adjust float level or re-jet, you must remove the top plate of the carb.

the jets are in the bowl assembly and the float level is adjusted by turning the top place upside down and measuring the distance between the top plate gasket and the top of the float.

First picture, float bowl, showing the metering jets
Second picture, bottom of float bowl showing the accelerator pump tube.
Third picture, top late showing the atmospheric vent, inlet valve body, and a 2 piece venturi.
Fourth picture, nylon float and a rubber tipped inlet valve.
I've soaked the rubber tipped inlet valves in auto fuel, and seen the rubber expand and come off the valve.
 

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are any of you mechanics framiliar with aero accessories? that is who overhauled the carb .

Why wouldn't they send it back with it setup properly ? The mechanic already spent 2 hours "tuning" it before he returned the plane to me, now I have to pay him more to retune it ? IS it tough to tune these right or what ?
 
bobkiksass said:
are any of you mechanics framiliar with aero accessories? that is who overhauled the carb .

Why wouldn't they send it back with it setup properly ? The mechanic already spent 2 hours "tuning" it before he returned the plane to me, now I have to pay him more to retune it ? IS it tough to tune these right or what ?
Click to expand...

There is only 2 adjustments that can be done, idle speed, and idle mixture, they are pretty simple.

and other adjustments are a matter of try, and re-try the size of the metering jets.
 
bobkiksass said:
are any of you mechanics framiliar with aero accessories? that is who overhauled the carb .

Why wouldn't they send it back with it setup properly ? The mechanic already spent 2 hours "tuning" it before he returned the plane to me, now I have to pay him more to retune it ? IS it tough to tune these right or what ?
Click to expand...

You are beyond simple adjustments, call the accessory shop and tell them what is happening, you might get lucky, you might not


Oh and make sure the carb P/N is right for your engine, not just the M/N
 
I sent them an email describing the problems, mechanice is going to look at it on Friday CHA CHING. Im tired of paying to get this plane running right.

I read about the problems with the overhauled Kelly aerospace carbs for the O-200 and had told my mechanic about that. He promised that wouldn't be the case, but now that I look at aircraft accessories website, I see they sell Kelly aerospace products. If they overhauled my carb I guess its safe to guess that it is the same as the Kelly Aerospace Carb, with similar associated problems. Running too rich etc.

Am I screwed with this newly overhauled possibly Kelly carb ?

What has been people experience with getting these carbs to run right ?
 
and this is the same carb as I had before, just overhauled, so I assume the P/N is the right one if it was hooked to the motor before ?
 
what is the difference between a model number and a part number ? and how would I verify my carb is correct for the motor ?
 
bobkiksass said:
what is the difference between a model number and a part number ? and how would I verify my carb is correct for the motor ?
Click to expand...

Model # is just that, the model of the carburetor. To allow flexibility when the OEM installed the engine into a particular airframe, the TCDS usually does not specify which part # should be installed.

Of the MA3-SPA family there many different part #'s

10-2848, 10-3237, 10-4115, 10-4240, 10-4252, 10-4439, 10-4457, 10-5128, 10-4894 etc....

http://www.avstardirect.com/carburetors/applications
 
Last thought,

Carbs get tossed around in shipping a lot, what's the chance that the needle & float arm aren't ideally aligned? I shake them vertically up and down before installation...



Looks to me like evey other possibilty has been covered in the thread already.
 
I put a rebuilt carb on a PA-12 a couple of years ago and had similar problems, actually worse. I struggled with it for about a week but, as has been said, there are only a couple of adjustments you can make to the idle settings. Other than making certain you have no intake or primer leaks there's not much else you can do. I ended up calling the supplier and told them what was happening and they said it wasn't right, to send it back. They sent me another carb and it worked perfect.

I can't remember the name of the place, it was in Florida and I can't tell you what was actually wrong with the carb. All I know is that when they are right they work flawlessly without any hiccups and you shouldn't have to be fussing with it much.
 
Local guy fixed up the one on our 172 that had it running lean and not making rated power
 
bnt83 said:
Model # is just that, the model of the carburetor. To allow flexibility when the OEM installed the engine into a particular airframe, the TCDS usually does not specify which part # should be installed.

Of the MA3-SPA family there many different part #'s

10-2848, 10-3237, 10-4115, 10-4240, 10-4252, 10-4439, 10-4457, 10-5128, 10-4894 etc....

http://www.avstardirect.com/carburetors/applications
Click to expand...

What determines the part number? If they are all the same model what changes to make it a different Part Number.
 
Tom-D said:
What determines the part number? If they are all the same model what changes to make it a different Part Number.
Click to expand...

I don't have my Marvel books handy but I just rebuilt my Stromberg and I can say that the NA-S3A1 manual is 88 pages and it lists all of the different part numbers on separate pages called Difference Data Sheets. On them are the specs and part numbers for venturi, metering jet, discharge nozzle bore and bleed sizes, idle jets, needle valve diameter and minimum drop among other things so there definitely are differences.
 
Silvaire said:
I don't have my Marvel books handy but I just rebuilt my Stromberg and I can say that the NA-S3A1 manual is 88 pages and it lists all of the different part numbers on separate pages called Difference Data Sheets. On them are the specs and part numbers for venturi, metering jet, discharge nozzle bore and bleed sizes, idle jets, needle valve diameter and minimum drop among other things so there definitely are differences.
Click to expand...
"The answer" the size of the jets.
 
Part of it but, at least on the Strombergs, they have different specs for float needle drop, sizes and positions of bleeds etc.
 
Silvaire said:
Part of it but, at least on the Strombergs, they have different specs for float needle drop, sizes and positions of bleeds etc.
Click to expand...

MA3-SPA every thing is the same except the jet size.
 
So pulled the carb off, sent it back to the repair shop, they tested it said they cant find anything wrong with it. And are sending it back.

The mechanic thinks there could be something else the matter, one of the cylinders seems to show different burn than the others on the spark plugs. When looking in the cylinders with the spark plugs out, the mechanic says he can tell oil is getting past the seals on the one cylinder because he saw fuel in there. At least, I think thats what he said. Its weird because the plane burns no oil. He also noticed the exhaust pipe showed dark deposit like its running too rich.

He thinks it could be the valve on one of the cylinders. When the annual happened he bore scoped the cylinder to make sure the valve was working and told me it was, now he wants to do it again ?

He told me "hes my friend, and to anyone else he would recommend to "top" the motor and start pulling cylinders. But if it were his plane he would want to see more signs indicating what was actually wrong"

What I dont get is if the carb is working right, how come when I pull the mixture out when idling it goes from running sounding like its hitting off @ 600-700 rpm to suddenly running much smoother at 900-1000 rpm. Its like a switch gets flipped ?

My pocket book and my patience are wearing thin with this shop, and the idea of having to top my motor with only 300 hrs on it seems ridiculous. My motor was overhauled 9 years ago, and he says that with that little of use in 9 years he wouldnt be surprised if some corrosion affected it. Ive put around 80 hrs on it in the last year since I bought it, and these problems have just started showing up last 20 hrs. Really frustrating
 
bobkiksass said:
...What I dont get is if the carb is working right, how come when I pull the mixture out when idling it goes from running sounding like its hitting off @ 600-700 rpm to suddenly running much smoother at 900-1000 rpm. Its like a switch gets flipped ?...
Click to expand...

Normally that means your idle circuit is too rich and that is adjusted by that big knurled needle valve but I guess that's already been tried.

As much as I want to sympathize with your mechanic I can't fathom how, faced with a difficult to diagnose problem, he could come to the conclusion that a top overhaul is gonna fix it. Also, although I'm not a big believer in borescope peeks telling you anything on a cylinder that displays proper compression test results (don't want to open that discussion again) but even if I were and I thought maybe I just missed something the first time I looked I'd just do it again to be sure - I wouldn't charge you a second time. Having to take a second look is not due to any fault of yours.
 
Does the idle mixture affect the full rich mixture at wide open throttle?

Is there a mixture adjustment to adjust how rich "full rich" is at wide open throttle ?

is it possible for the carb to be too rich at wide open throttle where it fouls out the plugs ?

If the idle mixture was too rich and you idled on the ground for a long time, is it possible for the plugs to get fouled on the ground and then they cause roughness at full throttle in flight a few minutes later? Im wondering if it fowled up the plugs on the ground and then its possible the roughness happened while climbing out. That seemed to be what I experienced.

When I spoke to the carb shop they said to send the carb back because if it caused it to stumble from being too rich at wide open they wanted to double check it. Because I had this conversation with the carb shop, the mechanic suggested to pull the carb and send it back before adjusting the idle mixture a second time.
 
bobkiksass said:
Does the idle mixture affect the full rich mixture at wide open throttle? ...
Click to expand...

No

bobkiksass said:
...Is there a mixture adjustment to adjust how rich "full rich" is at wide open throttle ? ...
Click to expand...

No

bobkiksass said:
...is it possible for the carb to be too rich at wide open throttle where it fouls out the plugs ?...
Click to expand...

Yes

bobkiksass said:
...If the idle mixture was too rich and you idled on the ground for a long time, is it possible for the plugs to get fouled on the ground and then they cause roughness at full throttle in flight a few minutes later? ...
Click to expand...

Yes

bobkiksass said:
...the mechanic suggested to pull the carb and send it back before adjusting the idle mixture a second time.
Click to expand...

Not sure what "adjusting the idle mixture a second time" means. You'd adjust it to get the 50-100 rpm rise at idle cutoff transition and if you had that why would you adjust it again? If you didn't have it then you're not done adjusting it the "first time"
 
Before you do anything you need to get your facts correct. Try googling a Cessna 150 maintenance manual and reading how to set idle mixture, which is adjustable with the carb on the engine.
 
So if the carb is running too rich when "full rich" at wide open throttle, how is it adjusted to lean it out ?
 
bobkiksass said:
So if the carb is running too rich when "full rich" at wide open throttle, how is it adjusted to lean it out ?
Click to expand...

For standard temperature at sea level you don't. The carburetor is built for the specific engine you have and it's the sizes of the jets, bleeds, venturi that determines that. If it's running too rich it's because something is wrong, not because of a mis-adjustment. Now if you're at 8,000 feet and it's 89 degrees out that's a different story. That's why there is a mixture control.
 
Have the plugs been looked at since it was all loaded up the first time? If the plugs are full of crap no amount of messing with the carb will do anything.
 
As well as the timing, clean air filter? no intake leaks? The carburetor gets adjusted after EVERYTHING else has been set right. It's the final tuning step.
 
There has to be some eaa. or YouTube videos online that will help bob put it all together. im away from my computer so goodluck.
 
Probably the best advice i can give here is find a competent mechanic because he doesn't know squat, or there is horrible communication or both.
 
bobkiksass said:
So if the carb is running too rich when "full rich" at wide open throttle, how is it adjusted to lean it out ?
Click to expand...

The red knob next to the throttle


Normal "knocking" of the O-200 http://www.youtube.com/watch?v=nEnXXCSG9FA they have their own distinct sound. Roughness at initial start could be a number of things, like over priming, oil fouled plugs, both of which take a minute to clear out as the engine warms up. Completely normal

All about carbs:
http://www.kellyaerospace.com/articles/Accessory_AMT.pdf
 
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Silvaire said:
For standard temperature at sea level you don't. The carburetor is built for the specific engine you have and it's the sizes of the jets, bleeds, venturi that determines that. If it's running too rich it's because something is wrong, not because of a mis-adjustment. Now if you're at 8,000 feet and it's 89 degrees out that's a different story. That's why there is a mixture control.
Click to expand...


In other words in a perfect world you don't need to touch the mixture.
In the real world, even near sea level at standard temperature, you may need to pull on the red knob to prevent fouling. O-200's don't do well on 100LL fuel, and if you are spending lots of time idling around on the ground during taxi, without taking actions to prevent fouling, your probably gonna foul them anyway.

1 hour with a seasoned Cessna 150 flight instructor could save you a lot of headaches and money. Learn how to run the engine on the ground and lean in the air.
 
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bnt83 said:
In other words in a perfect world you don't need to touch the mixture.
In the real world, even near sea level at standard temperature, you may need to pull on the red knob to prevent fouling. O-200's don't do well on 100LL fuel, and if you are spending lots of time idling around on the ground during taxi, without taking actions to prevent fouling, your probably gonna foul them anyway...
Click to expand...

True but he was asking about wide open throttle full power, not idle. At standard pressure and temperature, even with 100LL, there should be no fouling of plugs if the carburetor and everything else is in order.
 
bobkiksass said:
So pulled the carb off, sent it back to the repair shop, they tested it said they cant find anything wrong with it. And are sending it back.

The mechanic thinks there could be something else the matter,
Click to expand...

Well NO Scat,,

you can not get that much fuel out of the idle circuit to effect the RPM that much. you are getting fuel from another source.

The carb has been on the flow bench at the OVHL shop and it works there? then the only other place to get fuel is the Primer system. cap it off and see what changes.
 
what affect does the carb going from being a 2 piece venutri to one piece venturi ?

The one piece venturi I read runs richer than 2 piece ? Does it really affect performance that much ?

After they send the carb back, no big rise on idle mixture cutoff... but there is still some "morning sickness" type sound when idling. My mechanic isnt comfortable with reaming the valves, I think Im going to have someone else take a look at it. The mechanic says it has a "tinny" noise and is pretty convinced something is up with the valves.
 
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